Lifting jack



July 31, 1928. 1,679,210

A. R. ESMOND LIFTING JACK Filed March 25, 1927 2 Sheets-Sheet 1 film/fygsmond July 31, 1928. 1,679,210

r A. R. ESMOND LIbTING JACK Filed March 25, 1927 2 Sheets-Sheet 2 3- 953 .3/

Patented July 31, 1928.

UNITED STATES ALVA RAY ESMOND, OF UNION GROVE, WISCONSIN.

LIF'IING- JACK.

Application filed March 25, 1927.

This invention relates to lifting jacks.

Objects of this invention are to provide a novel form of'lifting jack in which the utmost of simplicity is attained and the maximum strength.

Further objects are to provide a lifting jack in which a ratchet wheel is provided and rigidly and unitarily joined to the lifting screw, so that no auxiliary gears or additional mechanism is required for transforming the rocking motion of the handle into the rotar motion of the, lifting screw.'

Further objects are to provide a device which may be very readily constructed by ordinary machine shop methods, which is highly practical in operation, and which is provided with anti-friction bearings between the lifting head or shoe and the lifting screw.

An embodiment of the invention is shown in the accompanying drawings in which:

Figure 1 is an elevation of the jack partly broken away and showing the rocking lever in section;

Figure 2 is a sectional view on the line 22 of Figure i, the ratchet wheel being omitted;

Figure 3 is a vertical sectional view through the upper portion of the jack;

Figure t is a sectional view on the line H of Figure 1, with however the major port-ion of the rocking lever shown in full lines;

Figure 5 is a sectional view on the line 5-5 of Figure l.

' Referring to the drawings, it will be seen that the jack comprises a base 1 or main body portion flared at its lower end to provide an adequate supporting surface and is internally threaded adjacent its upper end. This base is preferably provided with square threads which receive the square threads of the lifting screw 2. This lifting screw, as may be seen particularly from Figure 3, is provided with an integral enlarged upper portion 3 which terminates in an upwardly projecting pin or stub shaft 4;, centrally located. The head 3 or enlarged portion of the screw is provided with a peripheral channel, indicated generally by the reference character 5 in Figure 3, within which the.

curved arms (5 of the manipulating handle or lever operate. This channelled or recessed portion of the head 3 of the screw is also formed with a plurality of flat faced teeth forming a ratchet wheel 7, as shown Serial No. 178,467.

most clearly in Figure 4:. The notches in this portion which form the faces of the teeth are symmetrical, about radial lines, as is apparent from such figure.

The operating handle'consists, as stated,

of the curved arms 6 which embrace the head i 3 and fit within the groove portion 5 thereof.

These arms are pivotally joined bymea-ns of the pin 8 (see Figure l) and are provided with continuations or neck portions 9 which together form a cylindrical part. This cylindrical part is received withinthe socket 10v of a handle 11, asshown in Figure 4, so that when the handle is slipped in place it looks the two arms 6 against opening movement. The handle is provided with a pin 12 which projects inwardly into the socket 10, as shown most clearly in Figurefl, and this pin is adapted to enter the longitudinally extending slot 13 formed joint-1y in the two members 9 of the arms. On' sliding'the handle inwardly, the pintravels in- 1 wardly along the slot 13 and when the pin has arrived at the inner end of the slot, the handle may be given a rotary motion about its axis to cause the pin to travel into one of the lateral slots 14 formed in the member 9, and to seatwithin the recessed or enlarged portion 15 at the end of such lateral slot. This construction, therefore, provides for the rigid connection of the handle to the curved arms and also for the secure locking of the curved arms together.-

One of the curved arms is provided with a recessed port-ion 16 within which a spring pressed pawl 17 is pivoted, preferably by means of a pin cooperating withan elongated sloti18 to provide freedom of motion for the pawl and also to permit the seating of the curved rear end of the pawl within the curved socket port-ion 16 of the cutout 16, so that the pin is not called upon to bear the major pressure from the p'awl.-

. It is apparent, therefore, thatthe screw may be readily rotated by oscillating the handle back and forth. When it is desired to reverse the screw, it is merely necessary to slip-the handle from the members 9 of. the curved arms and open the arms out and thereafter turn them over so that the former bottom side becomes the upper side. There after, the handle is again slipped into place, and it will be seen that the pawl then operates the screw in the reverse direction upon oscillation of the handle. 1

The head 3 of the screw revolubly carries a bearing shoe 19 (see Figure 3) which is revolubly carried by the projecting. stub shaft 4 of the screw head. It is held in place by means of a. screw provided with a relatively largehead 20, as shown in Figure 3, so that it may freely rotate, but can not be inadvertently removed from the screw head. A threaded closure cap 21 is employed to seal the upper end of theenlarged opening 22 for the reception of the screw and prevent entrance of dirt. If desired, the upper face of the revolubly mounted head 19 may be provided with a bearing plate 23 which is centrally apertured and threaded, and is screwed upon the closure threaded plug 21. This not only provides for a bearing face of the shoe, but also forms in effect a lock nut for the threaded disc 21. I

In order to provide for the free rotation ofthe screw beneath the bearing shoe when the bearing shoe is heavily loaded, a plurality of balls 24 are positioned between the bottom of the shoe 19 and the top of the head 3, and are carried in annular grooves. These balls thus constitute a ball bearing of relatively great Width to prevent tilting and bindingof the shoe with reference to the screw head. i

The screw head is further provided with a plurality of upwardly projecting ratchet teeth 25 (see Figure 1) which cooperate with a plurality of relatively small pawls 26 pivotally carried by the bearing shoe 19. These pawls are provided with shoulders 2'? (see Figure 1) which are adapted to be engaged by lugs 28 carried by releasing ring 29. The releasing ring is guided upon the shoe 19 and is provided with a manipulating handle 30 (see Figures 1 and 5) by means of which it may be readily operated. Thus, when it is desired to lower the screw the handle 30 (see Figure 5) is rocked to lift all of the pawls 26 from engagement with the teeth 25. The screw is then reversely rotated and the jack is consequently lowered.

The load upon the shoe prevents its rotation and consequently such shoe may readily carry the pawls 26.

It will be seen that a very sturdy and compact lifting jack has been provided by this invention for it is obvious that when the device is not in use the manipulating handle may be readily removed and stored adjacent the jack proper, so that the stored device occupies the minimum of space.

It will be seen further that the utmost simplicity coupled with extreme strength is secured by this construction, and it is to be.

noted further that the device may be readily produced and easily operated.

Although the invention has been described in considerable detail, such description is intended as illustrative rather than limiting as.

;larged head having a peripheral channel and having ratchet teeth, a pair of. curved arms embracing said head and fitting within said channel, one of said arms being provided with a pawl cooperating with said ratchet teeth, and a handle for operating said arms, said head having an upwardly projecting stub shaft, and a shoe revolubly mounted upon said stub shaft. 7

2. A lifting jack comprising a body portion provided with an internally threaded vertical aperture, a screw cooperating with said aperture and havin an enlarged head provided with ratchet teeth, curved pivoted arms embracing said head and provided with a pawl cooperating with said atchet teeth and having outwardly projecting portions, a

handle having a socket for the reception of the outwardly projecting portionsof said arms and for oscillating said arms, ashoe pivotally carried by the upper end of said head, anti-friction bearings interposed between said shoe and said head, and ratchet mechanism carried jointly by said shoe and said head.

3. A lifting jack comprising a body portion provided with an internally threaded, vertical aperture, a screw cooperating with said aperture and having an enlarged head provided with ratchet teeth, curved arms embracing said head and provided with a pawl cooperating with said ratchet teeth, a handle for oscillating said arms, a shoe pivotally carried by the upper end of said head, anti-friction bearings interposed between said shoe and said head, and ratchet mechanism carried jointly by said shoe and said head, and manually controlled means for releasing said last mentioned ratchet mechamsm.

In. testimony that I claim the foregoing I have hereunto set my hand at Union Grove, in the county of Racine and State of Usconsin.

ALVA RAY ESMOND. 

